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Dimas [21]
3 years ago
11

Find an explicit formula for the arithmetic sequence 12, 5, -2, -9,...

Mathematics
1 answer:
Vadim26 [7]3 years ago
4 0

Answer:

an = 12 -7(n-1)

an = 19-7n

Step-by-step explanation:

The explicit formula for an arithmetic sequence is

an = a1 +d(n-1) where a1 is the first term and d is the common difference

a1 =12

We find d by taking the second term and subtracting the first term

d = 5-12

d = -7

an = 12 -7(n-1)

We can simplify this

an = 12 -7n+7

an = 19-7n

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In order for a vaccine to be effective, it should reduce a person's chance of acquiring a disease. Consider a hypothetical vacci
Dahasolnce [82]

Here is the full question.

In order for a vaccine to be effective, it should reduce a person's chance of acquiring a disease. Consider a hypothetical vaccine for malaria‚- a tropical disease that kills between 1.5 and 2.7 million people every year.1 Suppose the vaccine is tested with 700 volunteers in a village who are malaria-free at the beginning of the trial. Three hundred of the volunteers will get the experimental vaccine and the rest will not be vaccinated. Suppose that the chance of contracting malaria is 10% for those who are not vaccinated.

Construct a two-way table to show the results of the experiments if:

(a) The vaccine has no effect

(b) The vaccine cuts the risk of contracting malaria in half

Answer:

Step-by-step explanation:

From the given information above:

Suppose, there is no effect from the vaccine, the risk of having malaria for vaccine & no vaccine is equal to 0.1

Now, the Probability of not having malaria if vaccinated or no vaccinated = 1 - 0.1 = 0.9

Therefore: the table is shown below as follows:

                             Malaria              No Malaria                Total

Vaccinated          300 × 0.1 = 30     300 × 0.9 = 270    300

No Vaccine          400 × 0.1 = 40    400 × 0.9 = 360      700-300 = 400

Total                     40 + 30 = 70      270 + 360 = 630       700

(b)

The risk of malaria for vaccinated if the vaccine cuts the risk of contracting malaria in half are equal to 0.1/2 = 0.05

Thus; the probability of not getting malaria if vaccinated = 1 - 0.05 = 0.95

The table can then be computed as follows:

                             Malaria                No Malaria                 Total

Vaccinated       300 × 0.05 = 15     300 × 0.95 = 285       300

No Vaccine      400 × 0.1 = 40         400 × 0.9 = 360         700-300 = 400

Total                 40 + 15 = 55             285 + 360 = 645       700

7 0
3 years ago
PLEASE HELP!!!!!!!!! WILL MARK BRAINLIEST!!
svet-max [94.6K]

Answer:

b=-0.0019a + 215

at 2500 ft, b=210.25 degrees F

Step-by-step explanation:

First find the slope. a=altitude, b = temperature

slope is b2-b1 / a2-a1

points are (8200, 199.42) and (4700, 206.07)

(206.07 - 199.42) / (4700-8200)

= 6.65/ -3500

= - 0.0019

we have b = -0.0019a + intercept

plug in a point to find intercept

199.42 = -0.0019*8200 + intercept

intercept = 199.42 + 15.58 = 215

b=-0.0019a + 215

at a=2500 ft, substitute into equation

b= -0.0019*2500 + 215

= -4.75 + 215

= 210.25 degrees F

please give thanks by clicking heart button :)

4 0
2 years ago
The total cost C dollars, that a shop charges to print T shirts C = 45 + 7n , is the number of shirts ordered. Coach Dell paid 2
Lesechka [4]

Answer:

i think the answer is 23

Step-by-step explanation:

well the equation says c=45+7n so the total cost is 206 . i subtracted 45 from 206 leaving me with 161 then i divided that by 7 leaving me with 23

8 0
3 years ago
Explain this please!
vazorg [7]

Answer:

435 ft

Step-by-step explanation:

area of triangle:

A = (b x h) : 2

A = (15 x 4) : 2

A = 60 : 2

A = 30 ft

area of rectangle:

A = b x h

A = 25 x 15

A = 375 ft

area of the yard = area of the triangle + area of the triangle + area of the rectangle (Here, both triangles have the same area.)

area of the yard: 30 + 30 + 375 = 435 ft.

So, the area of the yard is 435 ft.

I hope this was helpful. :)

Please, do me Brainliest!

5 0
2 years ago
What is the slope and y intercept
Vera_Pavlovna [14]
Slope= -2/8
Y-int= -2
5 0
3 years ago
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